Android 组件Gallery和GridView示例讲解

<?xml version="1.0" encoding="utf-8"?><framelayout android:layout_height="fill_parent" android:layout_width="fill_parent" xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/FrameLayout01"><imageview android:layout_height="fill_parent" android:layout_width="fill_parent" android:id="@+id/ImageView01" android:src="@drawable/wallpaper_0"></imageview><gallery android:layout_height="wrap_content" android:layout_width="fill_parent" xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/Gallery01" android:spacing="5dp"></gallery></framelayout>

<?xml version="1.0" encoding="UTF-8"?><resources>  <declare -styleable="" name="HelloGallery">    <attr name="android:galleryItemBackground">  </attr></declare></resources>

package android.basic.lesson13;import android.app.Activity;import android.content.Context;import android.content.res.TypedArray;import android.os.Bundle;import android.view.View;import android.view.ViewGroup;import android.widget.AdapterView;import android.widget.AdapterView.OnItemClickListener;import android.widget.BaseAdapter;import android.widget.Gallery;import android.widget.ImageView;import android.widget.Toast;public class MainHelloGallery extends Activity {  /** Called when the activity is first created. */  @Override  public void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.main);    //定义UI组件    final ImageView iv= (ImageView)findViewById(R.id.ImageView01);    Gallery g = (Gallery) findViewById(R.id.Gallery01);    //设置图片匹配器    g.setAdapter(new ImageAdapter(this));    //设置AdapterView点击监听器，Gallery是AdapterView的子类    g.setOnItemClickListener(new OnItemClickListener() {      @Override      public void onItemClick(AdapterView<?> parent, View view,          int position, long id) {        //显示点击的是第几张图片        Toast.makeText(MainHelloGallery.this, "" + position,            Toast.LENGTH_LONG).show();        //设置背景部分的ImageView显示当前Item的图片        iv.setImageResource(((ImageView)view).getId());      }    });  }  //定义继承BaseAdapter的匹配器  public class ImageAdapter extends BaseAdapter {    //Item的修饰背景    int mGalleryItemBackground;    //上下文对象    private Context mContext;    //图片数组    private Integer[] mImageIds = { R.drawable.wallpaper_0,        R.drawable.wallpaper_1, R.drawable.wallpaper_2,        R.drawable.wallpaper_3, R.drawable.wallpaper_4,        R.drawable.wallpaper_5, R.drawable.wallpaper_6,        R.drawable.wallpaper_7, R.drawable.wallpaper_8,        R.drawable.wallpaper_9 };    //构造方法    public ImageAdapter(Context c){      mContext = c;      //读取styleable资源    TypedArray a = obtainStyledAttributes(R.styleable.HelloGallery);    mGalleryItemBackground = a.getResourceId(      R.styleable.HelloGallery_android_galleryItemBackground, 0);    a.recycle();    }    //返回项目数量    @Override    public int getCount() {      return mImageIds.length;    }    //返回项目    @Override    public Object getItem(int position) {      return position;    }    //返回项目Id    @Override    public long getItemId(int position) {      return position;    }    //返回视图    @Override    public View getView(int position, View convertView, ViewGroup parent) {      ImageView iv = new ImageView(mContext);      iv.setImageResource(mImageIds[position]);      //给生成的ImageView设置Id，不设置的话Id都是-1      iv.setId(mImageIds[position]);      iv.setLayoutParams(new Gallery.LayoutParams(120, 160));      iv.setScaleType(ImageView.ScaleType.FIT_XY);      iv.setBackgroundResource(mGalleryItemBackground);      return iv;    }  }}